Method and system for displaying an image

ABSTRACT

There is disclosed a method and apparatus for displaying an image that includes selecting a camera unit horizontal field of view (FOV) of about eighteen degrees and selecting a system magnification of between 0.4 and 1.0. The method and apparatus also includes determining an aspect ratio for the image based on the selected camera unit horizontal FOV and the selected system magnification, receiving energy from a scene for forming the image and displaying the image on a display.

TECHNICAL FIELD OF THE INVENTION

[0001] This invention relates generally to vision systems and, moreparticularly, to a method and system for displaying an image.

BACKGROUND OF THE INVENTION

[0002] During daylight hours, the driver of a vehicle is able to detectand recognize objects that would be difficult, if not impossible, todetect or recognize at night. For example, on a sunny day, a deerapproximately 500 meters ahead of a vehicle should be readily detectableand recognizable. At night, however, particularly when the headlightsprovide the only illumination, the deer will not be detectable, muchless recognizable, at that distance because it will be beyond the rangeof the headlights. Moreover, by the time the driver detects the deer,and well before recognizing what it is, the vehicle will be much closerto the deer than during daylight. Accordingly, the risk of a resultingaccident is much higher at night than during the day.

[0003] Consequently, in order reduce the risk of accidents, night visionsystems have been developed to supplement the driver's vision. Oneexample of a night vision system is included in U.S. Pat. No. 5,781,243entitled “Display Optimization for Night Vision Enhancement Systems.”Some night vision systems include an infrared camera unit mounted in thegrill of the vehicle and an image source mounted in the vehicle'sdashboard. The camera unit gathers information regarding the scene infront of the vehicle, and the image source projects an image derivedfrom the information onto the windshield for display.

[0004] Using the windshield for image display, however, has severaldrawbacks. For example, the illumination of the image may be poorbecause a large amount of light is lost due to refraction. As anotherexample, the image may be distorted because of the windshield's varyingcurvature. To address these drawbacks, several night vision systems areproposing to use a magnifying optical element mounted to the dashboardas a display device for the driver. Because of vision and aestheticconsiderations, there is a continuing demand to reduce the size of thedisplay device. Typical displays provide excess information which mayconfuse the driver. For example, the excess information may distort thedepth perception of the driver, particularly when the image displayedfor the driver is one that has been minified.

SUMMARY OF THE INVENTION

[0005] The present invention provides a method and system for displayingan image that substantially eliminates or reduces at least some of thedisadvantages and problems associated with previous methods and systems.

[0006] In accordance with a particular embodiment of the presentinvention, a method for displaying an image includes selecting a cameraunit horizontal field of view (FOV) of about eighteen degrees andselecting a system magnification of between 0.4 and 1.0. The method alsoincludes determining an aspect ratio for the image based on the selectedcamera unit horizontal FOV and the selected system magnification,receiving energy from a scene for forming the image and displaying theimage on a display.

[0007] The selected horizontal FOV may comprise eighteen degrees, andthe system magnification may comprise approximately 0.55. The determinedaspect ratio for the image may comprise approximately 10:3.3 or 3.1. Themethod may also include converting the energy received into informationrepresentative of the received energy and forming the image using theinformation representative of the received energy. Displaying the imageon a display may comprise projecting the image onto a fold mirror andreflecting the visible image to an imaging mirror using the fold mirror.

[0008] In accordance with another embodiment, a system for displaying animage includes a camera unit having a horizontal FOV selected to beabout eighteen degrees and a system magnification selected to be between0.4 and 1.0. The system includes a display coupled to the camera unit.The display is operable to display the image. The image has an aspectratio determined based on the selected camera unit horizontal FOV andthe selected system magnification.

[0009] The system may further include a lens system operable to directenergy from a scene toward a detector and a display unit comprising thedisplay. The display unit may be coupled to the detector and may beoperable to form the image using information received from the detector.The detector may include an array of detector elements, each detectorelement operable to receive energy from a portion of the scene and toconvert the received energy into information representative of thereceived energy and to send the information associated with at leastsome of the detector elements to the display unit. The display unit maycomprise a liquid crystal display (LCD) operable to project the imageonto a fold mirror. The fold mirror may be configured to reflect thevisible image to an imaging mirror.

[0010] Technical advantages of particular embodiments of the presentinvention include an auxiliary vision system having a camera unit with ahorizontal FOV of about eighteen degrees, a selected systemmagnification of approximately 0.4 to 1.0 and an aspect ratio determinedbased on the system magnification and the horizontal FOV of the cameraunit. Such a system is particularly suited to present an auxiliary imagethat better enables a driver to properly perceive depth in the image.Furthermore, the horizontal FOV of the camera unit of about eighteendegrees presents a beneficial amount of horizontal information to thedriver to effectively see potential hazards in the roadway in front ofthe vehicle, especially in combination with a system magnificationselected between 0.4 and 1.0 and a displayed image aspect ratio based onsuch camera unit horizontal FOV and selected system magnification.Moreover, this horizontal FOV of the camera unit coupled with a selectedmagnification of between 0.4 and 1.0 can more effectively be utilizedand packaged in an auxiliary vehicle system.

[0011] Other technical advantages will be readily apparent to oneskilled in the art from the following figures, descriptions and claims.Moreover, while specific advantages have been enumerated above, variousembodiments may include all, some or none of the enumerated advantages.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] For a more complete understanding of particular embodiments ofthe invention and their advantages, reference is now made to thefollowing descriptions, taken in conjunction with the accompanyingdrawings, in which:

[0013]FIG. 1 is a diagrammatic view of a vehicle that includes oneembodiment of an auxiliary vision system in accordance with the presentinvention;

[0014]FIG. 2 is a diagrammatic view of the auxiliary vision system ofFIG. 1, showing in more detail the internal structure of a camera unitand a display unit of the auxiliary vision system;

[0015]FIG. 3 is a diagrammatic view of a camera unit coupled to adisplay unit in accordance with an embodiment of the present invention;

[0016]FIG. 4 is a graph illustrating the effect on depth perception ofdisplaying information that is proximate to a camera, in accordance withan embodiment of the present invention; and

[0017]FIG. 5 is a flowchart illustrating a method for displaying animage, in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0018]FIG. 1 is a diagrammatic view of a vehicle 10 incorporating oneembodiment of an auxiliary vision system 20 in accordance with anembodiment of the present invention. The auxiliary vision system 20includes a camera unit 30, which in the illustrated embodiment ismounted at the front of vehicle 10, in the middle of a front grill 12.The camera unit 30 is electrically coupled at 39 to a display unit 40,which is also a part of the auxiliary vision system 20. The display unit40 is of a type that is commonly known as a head-up display (HUD). Thedisplay unit 40 is mounted within a recess of a dashboard 14 of thevehicle 10, and can project a visible image for reflection by a foldmirror of display unit 40 onto a display 17 for viewing by the driver.Display 17 is recessed within dashboard 14 when auxiliary vision system20 is not in use.

[0019] The camera unit 30 is also electrically coupled to a computer 60at 69. The computer 60 is also part of the auxiliary vision system 20and provides instructions to camera unit 30 based on heading informationit receives from an angle encoder 70, which is coupled to a steeringcolumn 16 of vehicle 10 and electrically coupled to computer 60 at 79,and/or an inclinometer 80, which is coupled to the frame of vehicle 10and electrically coupled to computer 60 at 89. Angle encoder 70 andinclinometer 80, which are two types of sensors, are also a part ofauxiliary vision system 20. In general, any type of sensor that canprovide information regarding the heading of vehicle 10, such as, forexample, steering rate, inclination rate, and/or orientation, may beused in auxiliary vision system 20. Additionally, one, two, or evenseveral sensors may be used in different embodiments. Particularembodiments may not include an angle encoder or an inclinometer. Theauxiliary vision system 20 of FIG. 1 is discussed in more detail later.

[0020] When a driver is operating a vehicle at night, the driver'sability to see the road ahead is substantially more limited than wouldbe case for the same section of road during daylight hours. This isparticularly true in a rural area under conditions where there is littlemoonlight, there are no street lights, and there are no headlights ofother vehicles. If an animal such as a deer happens to wander into theroad at a location 500 meters ahead of the vehicle, the driver wouldreadily notice and recognize the deer during daylight hours, whereas atnight the deer may initially be beyond the effective reach of theillumination from the vehicle's headlights. Moreover, even when theheadlights begin to illuminate the deer, the driver may not initiallynotice the deer, because the deer may be a brownish color that isdifficult to distinguish from the surrounding darkness. Consequently, atthe point in time when the driver first realizes that there is a deer inthe road, the vehicle will be far closer to the deer in a nighttimesituation than would be the case during daylight hours. There are manyother similar high risk situations, for example, where a pedestrian iswalking along the road.

[0021] One purpose of auxiliary vision system 20 of FIG. 1 is to providethe driver of the vehicle 10 with information above and beyond thatwhich the driver can discern at night with the naked eye. In thisregard, the camera unit 30 can detect infrared information at a distancewell beyond the effective reach of the headlights of the vehicle 10. Inthe case of a life form such as an animal or a human, the heat signatureof the life form, when presented in an infrared image derived from thecamera unit 30, will usually have a significant contrast in comparisonto the relatively hotter or cooler surrounding natural environment. Asdiscussed above, this is not necessarily the case in a comparablenighttime image based on visible light.

[0022] Thus, in addition to the image that is directly observed by thedriver through the windshield of the vehicle based on headlightillumination and any other available light, the auxiliary vision system20 provides a separate and auxiliary image, based on infrared radiation,that is reflected onto display 17. This auxiliary image can provide adetectable representation of lifeforms or objects ahead that are not yetvisible to the naked eye. Further, the auxiliary image can provide amuch more striking contrast than a visible image between the lifeformsor objects and the surrounding scene. Note that the auxiliary visionsystem 20 may also be useful during daylight hours to supplement theview of objects seen with natural light.

[0023] Camera unit 30 has particular horizontal and vertical fields ofview through which it detects an image. At least a portion of this imageis ultimately displayed as the auxiliary image to the driver usingdisplay 17. This auxiliary image may include substantially all of thehorizontal portion of the image detected by the camera unit 30. However,a vertical portion of the image detected by the camera unit 30 may notbe displayed to the driver in the auxiliary image on display 17 so thatthe driver is better able to properly perceive depth in the auxiliaryimage displayed.

[0024]FIG. 2 is a diagrammatic view of the auxiliary vision system 20 ofFIG. 1, showing in greater detail the internal structure of both thecamera unit 30 and the display unit 40, in accordance with an embodimentof the present invention. More specifically, thermal radiation from ascene 50 enters the camera unit 30 and passes through a lens system 32and a chopper 34 to a detector 36. The lens system 32 directs theincoming radiation onto an image plane of the detector 36.

[0025] In the disclosed embodiment, the chopper 34 is a rotating disk ofa known type. As the chopper 34 is rotated, it modulates the incominginfrared radiation to the detector 36.

[0026] Also in the disclosed embodiment, the detector 36 is acommercially available focal plane array or staring array detector,which has a two-dimensional matrix of detector elements, where eachdetector element produces a respective pixel of a resulting image. Inparticular, detector 36 is an uncooled pyroelectric barium strontiumtitanate (BST) detector, although numerous other types of detectorswould also be useful in auxiliary vision system 20. Other such types mayinclude vanadium oxide, thin-film ferrolectric or alpha-siliconbolometers.

[0027] The circuitry 38 is provided to control the detector 36 and readout the images that it detects, and also to synchronize the chopper 34to operation of the detector 36. Further, based on information fromcomputer 60, the circuitry 38 sends the information obtained fromdetector 36 through the electrical coupling 39 to the circuitry 42within the display unit 40.

[0028] The circuitry 42 controls a liquid crystal display (LCD) 44,which in the disclosed embodiment has a two-dimensional array of pixelelements. In this embodiment, the display unit 40 displays an imagehaving a horizontal to vertical aspect ratio of 10:3.3 or 3:1. Thecircuitry 42 takes successive images obtained from the detector 36through circuitry 38, and presents these on the LCD 44. The LCD 44 mayinclude backlighting that makes the auxiliary image on LCD 44 visible atnight.

[0029] This auxiliary image is projected onto a fold mirror 48 thatreflects the image so as to be directed onto display 17, creating avirtual image for the driver. In the illustrated embodiment, display 17comprises an imaging mirror. Although fold mirror 48 and display 17 areshown diagrammatically in FIG. 2 as planar components, each may have arelatively complex curvature that is known in the art. The curvature mayalso provide some optical power. Display 17 is movably supported, andits position at any given time is determined by a drive mechanism 46.Using the drive mechanism 46, the driver may adjust the display 17 sothat it is in a viewing position comfortable for that particular driver.Once the driver has finished adjusting the display 17 to a suitableposition, it remains in that position during normal operation of theauxiliary vision system 20.

[0030] It should be understood that even though in the illustratedembodiment display 17 comprises an imaging mirror, in other embodimentsthe auxiliary image may be displayed directly for view by the driver,without reflection off a mirror or other component. For example, in someembodiments a driver may view the image directly on an LCD, cathode raytube (CRT) display or other type of direct view display.

[0031]FIG. 3 illustrates a camera unit 150 for use with the auxiliaryvision system 20 and employing an infrared sensor and an optical system152 that focuses equally-spaced points 154 along a roadway 156 onto afocal plane array 158. The focal plane array 158 may be an array ofuncooled infrared detectors from which an image is ultimately suppliedvia suitable cables 160 to a display 162.

[0032] Optical system 152 is a wide-angle optical system, i.e., one thatincludes both near and far field points out in front of a vehicle. Insuch a system, equally-spaced points in object space are nonlinearlydistributed on the focal plane array 158. This nonlinear distribution ofoptical rays may create a misjudgment of distance in the driver's mind.More specifically, the points 154 which are closer to the vehicle createa greater nonlinear distribution on the focal plane array 158. Thus, inaccordance with the present invention a driver's depth perception isimproved by reducing in the auxiliary image the amount of informationdisplayed that is closer to the vehicle. The amount of such informationdisplayed is determined based on the amount of vertical informationdisplayed to the driver in the auxiliary image. Thus, by reducing theamount of vertical information displayed to the driver in the auxiliaryimage, then the amount of information closer to the vehicle that isdisplayed will be reduced. The driver's depth perception will thereforebe improved. In particular embodiments, the pointing angle of the cameraunit 30 may be elevated to reduce the amount of information closer tothe vehicle that is displayed to the driver.

[0033] For further explanation, FIG. 4 is a graph 180 illustrating threecurves representing the relationship between the distance (in meters) ofvarious points from a camera, plotted on the x-axis, and the tangent ofthe angle formed by the horizontal and a line from the camera to eachpoint (for example, angles 164 of FIG. 3), plotted on the y-axis. Eachcurve represents a relationship with the camera at a particular height.Curve 182 represents a relationship when the camera is at a height of0.5 meters, curve 184 represents a relationship when the camera is at aheight of 1.0 meter and curve 186 represents a relationship when thecamera is at a height of 2.0 meters.

[0034] From graph 180, one can observe that as the distance from thecamera increases, each curve becomes more linear. However, when thedistance from the camera is closer to zero (especially, for example,when the distance is less than approximately sixty meters), each curveis non-linear. This is indicative of the distortion in depth perceptionthat can occur when viewing on a display an object that is relativelycloser to the vehicle.

[0035] The importance of the overall system magnification between anobject in the real world and an object as viewed on the display shouldalso be noted. The system magnification may be computed as follows:

system magnification=θ_(D)/θ_(O)

[0036] where

[0037] θ_(O)=angular subtense of feature in object space

[0038] θ_(D)=angular subtense of feature as viewed on display at thedriver's eye position.

[0039] The angular subtense θ_(D) may be computed as follows:

θ_(D)=2 tan⁻¹((A/2)/B)

[0040] where

[0041] A=linear dimension of displayed feature

[0042] B=distance of driver's eye to display.

[0043] It should be noted that the angular subtense θ_(D) for a head-updisplay is defined by the field of view of the device, which is definedby the magnifying power of the projection mirror.

[0044] Given the system magnification relationship, it is noted that asystem magnification which is less than 1.0 creates a problem in judgingdepth in the displayed auxiliary image. If the system magnification werealways held to the value 1, the field of view (FOV) of the camera unit30 would have little effect on the displayed information. This, however,requires a very large display 17 for wide field angles in the cameraunit 30. Since a large display is impractical to package in manyvehicles, the relationship described above with respect to systemmagnification becomes very useful in determining the amount ofinformation to provide in the auxiliary image when a wide field angle isdesired for the horizontal FOV of the camera unit 30.

[0045] Given the explanation discussed above, it is noted that adriver's depth perception of an auxiliary image is affected by theamount of information closer to the vehicle that is displayed and themagnification of the image. As stated above, one can reduce the amountof information closer to the vehicle that is displayed by reducing theamount of vertical information. It is desired to display in theauxiliary image substantially all of information in the horizontal FOVof the camera unit 30. Thus, to change the amount of verticalinformation displayed, the aspect ratio (the ratio of horizontal tovertical) of the image displayed on the display 17 may be modified. Themagnification of an auxiliary vision system 20 may be changed bychanging the horizontal FOV of the camera unit 30, the horizontaldimension of the image on display 17 or the distance between thedriver's eye and the display 17.

[0046] Therefore, optimizing an auxiliary image displayed by display 17is achievable by selecting a horizontal FOV for the camera unit 30,selecting a magnification for auxiliary vision system 20 and determiningan aspect ratio for the displayed image based on such selections inorder to reduce distortion in a driver's depth perception. In particularembodiments, the horizontal FOV of the camera unit 30 is about eighteendegrees (for example, between fifteen and twenty-one degrees or betweenfifteen and twenty-five degrees). In such embodiments, the systemmagnification may range from approximately 0.4 to 1.0. An aspect ratiofor the image displayed on display 17 is selected in order to betterenable the driver to properly perceive depth in the auxiliary image. Inone embodiment, the horizontal FOV of camera unit 30 is eighteendegrees, the system magnification is approximately 0.55 and the aspectratio of the displayed image is approximately 10:3.3.

[0047] It has been determined that an auxiliary vision system 20 havinga camera unit 30 with a horizontal FOV of about eighteen degrees, aselected system magnification of approximately 0.4 to 1.0 and an aspectratio determined based on the system magnification and the horizontalFOV of the camera unit 30 is particularly suited to present an improvedauxiliary image that better enables a driver to properly perceive depthin the image. For example, a driver of a vehicle that includes anauxiliary vision system 20 as described herein is better able to judgethe size of objects in front of the vehicle that are shown on display17. Furthermore, the horizontal FOV of the camera unit 30 of abouteighteen degrees presents a beneficial amount of horizontal informationto the driver to effectively see potential hazards in the roadway infront of the vehicle, especially in combination with a systemmagnification selected between 0.4 and 1.0 and a displayed image aspectratio based on such camera unit horizontal FOV and selected systemmagnification. Moreover, this horizontal FOV of camera unit 30 coupledwith a selected magnification of between 0.4 and 1.0 can moreeffectively be utilized and packaged in an auxiliary vehicle system 20.

[0048] A displayed image aspect ratio determined based on a horizontalFOV of about eighteen degrees and a system magnification of between 0.4and 1.0 also optimally minimizes the number of eye fixations required toview the displayed image. The number of eye fixations required toassimilate information from a display is directly proportional toangular area. Thus, minimizing the number of eye fixations is desirablefor safety and efficiency in a display for aircraft, automobiles,trucks, recreational vehicles, or any other form of moving vehicle. Adisplayed image having an aspect ratio determined as discussed aboveminimizes the number of eye fixations by minimizing the amount ofdisplayed information for the viewer to observe.

[0049]FIG. 5 is a flowchart illustrating a method for displaying animage, in accordance with an embodiment of the present invention. Themethod begins at step 200 where a camera unit 30 horizontal FOV of abouteighteen degrees is selected. In particular embodiments, the selectedcamera unit 30 horizontal FOV may be approximately between fifteen andtwenty-five degrees. At step 202, a system magnification of between 0.4and 1.0 is selected. At step 204, an aspect ratio for the image isdetermined based on the selected camera unit horizontal FOV and theselected system magnification. The aspect ratio is determined based onthe selected camera unit 30 horizontal FOV and system magnification suchthat an observer properly and effectively perceives depth in a displayimage.

[0050] The method continues at step 206 where energy from a scene 50 isreceived at each of a plurality of detector elements. At step 208, theenergy received at each detector element is converted into informationrepresentative of the energy received at step 206. At step 210, an imageis formed using the information representative of the received energy.At step 212, the image is displayed by projection by an LCD 44 onto afold mirror 48 for reflection onto an imaging mirror 17 for view by thedriver of a vehicle. Through the image, the driver may detect lifeformsor objects ahead that are not yet visible to the naked eye.

[0051] Although the present invention has been described in detail,various changes and modifications may be suggested to one skilled in theart. It is intended that the present invention encompass such changesand modifications as falling within the scope of the appended claims.

What is claimed is:
 1. A method for displaying an image on a display,comprising: selecting a camera unit horizontal field of view (FOV) ofabout eighteen degrees; selecting a system magnification of between 0.4and 1.0; determining an aspect ratio for the image based on the selectedcamera unit horizontal FOV and the selected system magnification;receiving energy from a scene for forming the image; and displaying theimage on a display.
 2. The method of claim 1, wherein selecting a cameraunit horizontal field of view (FOV) of about eighteen degrees comprisesselecting a camera unit horizontal FOV of between fifteen and twenty-onedegrees.
 3. The method of claim 1, wherein selecting a systemmagnification of between 0.4 and 1.0 comprises selecting a systemmagnification of approximately 0.5 to 0.6.
 4. The method of claim 1,wherein: selecting a camera unit horizontal field of view (FOV) of abouteighteen degrees comprises selecting a camera unit horizontal FOV ofeighteen degrees; selecting a system magnification of between 0.4 and1.0 comprises selecting a system magnification of approximately 0.55;and determining an aspect ratio for the image based on the selectedcamera unit horizontal FOV and the selected system magnificationcomprises determining an aspect ratio for the image of approximately10:3.3.
 5. The method of claim 1, wherein displaying the image on adisplay comprises reflecting the image onto an imaging mirror.
 6. Themethod of claim 1, wherein displaying the image on a display comprisesdisplaying the image on a liquid crystal display (LCD).
 7. A method fordisplaying an image on a display, comprising: selecting a camera unithorizontal field of view (FOV) of about eighteen degrees; selecting asystem magnification of between 0.4 and 1.0; determining an aspect ratiofor the image based on the selected camera unit horizontal FOV and theselected system magnification; receiving energy from a scene for formingthe image at each of a plurality of detector elements; converting theenergy received at each detector element into information representativeof the received energy; forming the image using the informationrepresentative of the received energy; and displaying the image on adisplay.
 8. The method of claim 7, wherein displaying the image on adisplay comprises projecting the image onto a fold mirror and reflectingthe visible image to an imaging mirror using the fold mirror.
 9. Asystem for displaying an image, comprising: a camera unit having ahorizontal field of view (FOV) selected to be about eighteen degrees; asystem magnification selected to be between 0.4 and 1.0; and a displaycoupled to the camera unit, the display operable to display the image,the image having an aspect ratio determined based on the selected cameraunit horizontal FOV and the selected system magnification.
 10. Thesystem of claim 9, wherein a camera unit having a horizontal field ofview (FOV) selected to be about eighteen degrees comprises a camera unithaving a horizontal FOV selected to be between fifteen and twenty-onedegrees.
 11. The system of claim 9, wherein a system magnificationselected to be between 0.4 and 1.0 comprises a system magnificationselected to be approximately 0.5 to 0.6.
 12. The system of claim 9,wherein: a camera unit having a horizontal field of view (FOV) selectedto be about eighteen degrees comprises a camera unit having a horizontalFOV selected to be eighteen degrees; a system magnification selected tobe between 0.4 and 1.0 comprises a system magnification selected to beapproximately 0.55; and the image having an aspect ratio determinedbased on the selected camera unit horizontal FOV and the selected systemmagnification comprises the image having an aspect ratio ofapproximately 10:3.3.
 13. The system of claim 9, wherein the displaycomprises the imaging mirror and further comprising a fold mirroroperable to display the image onto the imaging mirror.
 14. The system ofclaim 9, wherein the display comprises a liquid crystal display (LCD).15. A system for displaying an image, comprising: a camera unit having ahorizontal field of view (FOV) selected to be about eighteen degrees; asystem magnification selected to be between 0.4 and 1.0; a displaycoupled to the camera unit, the display operable to display the image,the image having an aspect ratio determined based on the selected cameraunit horizontal FOV and the selected system magnification; a lens systemoperable to direct energy from a scene toward a detector; a display unitcomprising the display, the display unit coupled to the detector, thedisplay unit operable to form the image using information received fromthe detector; and wherein the detector includes an array of detectorelements, each detector element operable to receive energy from aportion of the scene and to convert the received energy into informationrepresentative of the received energy and to send the informationassociated with at least some of the detector elements to the displayunit.
 16. The system of claim 15, wherein the display unit comprises aliquid crystal display (LCD) operable to project the image onto a foldmirror, the fold mirror configured to reflect the visible image to animaging mirror.
 17. The system of claim 15, wherein the detectorcomprises a vanadium oxide bolometer.
 18. The system of claim 15,wherein the detector comprises a thin-film ferrolectric bolometer. 19.The system of claim 15, wherein the detector comprises an alpha-siliconbolometer.